Mitsubishi Electric MELSEC iQ-R Series User Manual page 187

The following describes settings of each buffer memory area.
Buffer memory area
CAN ID n (CAN-ID n LW, CAN-ID n HW)
RTR/new/DLC
Data bytes
*1 When a receive message passes the filter set in 'Pre-defined Layer 2 message configuration' (Un\G6000 to Un\G6167), the reception
CAN-ID is updated. The CAN-ID, RTR/new/DLC, and data displayed in the receive message is always latest.
*2 b12 and b15 cannot be set to 1 at the same time.
*3 When b12 is set to 0, only the CAN-ID of an receive RTR frame is checked for a match with the ID of the user message.
When b12 is set to 1, the message will not be sent if the CAN-ID and DLC of the RTR frame do not match those of the user message.
Also, the corresponding message slot in 'Layer 2 RTR flags' (Un\G8350 to Un\G8352) will not turn on.
b12 can be set to 1 when parameter B is 6FFFH or 7FFFH.
*4 b15 sets whether to send a message as a send data frame or send RTR frame.
b15 can be set to 1 when parameter B is 5FFFH
b15 can be set to 1 when parameter C is 0, 2, or 4.
*5 When b8 is 1, a new message including new data has been received and stored.
If b9 is 1 but b8 is 0, the same message (same CAN-ID, DLC and data) has been received.
If b10 is 1, at least one message has been stored in the receive buffer while b8 was 1, which caused an overflow condition.
*6 In case the received DLC is lower than 8, unused data bytes are set to 00H.
*7 For the CAN-ID of a send message, the same CAN-ID as the CAN-ID of another send message cannot be used. If the same CAN-ID is
set, a parameter error occurs.
The following describes status of b8 to b10 of RTR/new/DLC for receive messages.
• New frame, no new data: b8 = 0, b9 = 1, b10 = 0
• New frame, new data: b8 = 1, b9 = 1, b10 = 0
• New frame, no new data, overflow: b8 = 0, b9 = 1, b10 = 1
• New frame, new data, overflow: b8 = 1, b9 = 1, b10 = 1
• No receive data: b8 = 0 or 1, b9 = 0, b10 = 0 or 1
Description
Transmit message
*7
Set the CAN-ID of the transmit message.
*2
■Upper byte
b12 = 1: RTR DLC precise check
b15 = 0: Send data frame
b15 = 1: Send RTR frame
■Lower byte
Set the number of bytes for send data (0 to 8)
Data bytes 1 to 8
The number of attached data bytes that is defined
by DLC
Receive message
Reception CAN-ID
■Upper byte
*3
00H = New data not received
*4
b8 = 1: New data received
*4
b9 = 1: New frame received
b10 = 1: Overflow
■Lower byte
*4
. Data length count (DLC) of the received CAN
frame
Received data bytes
*1
*5
*6
APPX
Appendix 2 Buffer Memory
A
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